Astronomy Stack Exchange
Astronomy Stack Exchange

Most Popular

more tags
1500 questions
150
votes
2 answers

How much gold is there in our sun?

XKCD 1944 claims that there is "more gold in the sun than water in the oceans". Is this really true?
Jakub Šturc
  • 1,379
  • 2
  • 8
  • 7
141
votes
3 answers

How loud would the Sun be?

Sound can't travel through outer space. But if it could, how loud would the Sun be? Would the sound be dangerous to life on Earth, or would we barely hear it from this distance?
Jamie
  • 1,179
  • 2
  • 8
  • 15
108
votes
1 answer

How can there be 1,000 stellar ancestors before our Sun?

I've heard from a few sources* recently that the Sun is a 1,000th generation star, meaning it had a thousand stars that came before it based on its heavy-element content. I understand that earlier stars' supernovae created the heavier elements and…
Benjam
  • 1,199
  • 2
  • 7
  • 7
94
votes
2 answers

Why is the discovery of merging neutron stars important?

I'm fairly certain people here will have heard about it, already, but apparently, two supernova leftovers clashed some 130 million years ago and some billion billion kilometres away ... What I haven't heard yet, however, is why we should care. I…
User1291
  • 993
  • 1
  • 6
  • 6
93
votes
6 answers

Does the Sun rotate?

The planets rotate as an after effect of their creation, the dust clouds that compressed span as they did so and the inertia has kept it rotating ever since. It's fairly easy to prove that planetary bodies are rotating just by watching their…
user96
86
votes
12 answers

Why don't astronomers use meters to measure astronomical distances?

In astronomy distances are generally expressed in non-metric units like: light-years, astronomical units (AU), parsecs, etc. Why don't they use meters (or multiples thereof) to measure distances, as these are the SI unit for distance? Since the…
Arne
  • 985
  • 1
  • 6
  • 8
85
votes
2 answers

Could the dinosaurs have seen the asteroid that killed them?

Wikipedia says the Chicxulub impactor is thought to have been a 10-15 km diameter object. Would it have been visible to a (human*) naked eye before impact? And if so, would it have appeared like a star that grew brighter and brighter each night? * I…
Robert
  • 955
  • 1
  • 6
  • 6
81
votes
6 answers

Is the Moon only 60x60 pixels?

In doing research on vision, I have learned that "20/20" vision corresponds to a visual acuity of being able to resolve details 1 arcminute in size, that most people have around 20/15 vision, and that due to the limits of physiology basically nobody…
Phrogz
  • 937
  • 1
  • 6
  • 10
77
votes
4 answers

How does the Earth move in the sky as seen from the Moon?

I just want to be sure I am visualizing this correctly, because it seems odd. The Moon is tidally locked to the Earth but there are wobbles to its motion due to libration. So from a point on the surface of the near side of the Moon, the Earth would…
kim holder
  • 1,569
  • 1
  • 10
  • 19
77
votes
2 answers

Can gravitational waves pass through a black hole?

As the title says, what happens when a gravitational wave approaches a black hole? I would presume that something interesting happens because of the way spacetime works near black holes but I have no knowledge to back it up.
dalearn
  • 823
  • 1
  • 7
  • 16
75
votes
5 answers

Why not take a picture of a closer black hole?

There are closer galaxies than Messier 87 for sure, even ours! It sparked my curiosity that they went with one 53 million light years away. Is there a reason for this?
Morgan
  • 733
  • 1
  • 5
  • 7
74
votes
2 answers

Is it dark inside the Sun?

This might sound like a strange question, but something got me thinking about it recently. The opacity of plasma in stellar interiors can get quite high, making for shorter free-paths for photons. In these conditions I guess that the light you could…
Swike
  • 3,916
  • 1
  • 15
  • 26
73
votes
6 answers

Why is only one side of the Moon visible from Earth?

Why do we only ever see the same side of the moon? If this is to do with gravity are there any variables which mean we might one day see more than we have before?
Rob
  • 849
  • 1
  • 7
  • 6
70
votes
3 answers

If a massive object like Jupiter flew past the Earth how close would it need to come to pull people off of the surface?

I understand this is a silly hypothetical but I'm asking for a 7 year old so please bear with me. Imagine an interstellar stray gas giant comes flying through our solar system. If we were not concerned that it would also steal our atmosphere and…
Yevgeny Simkin
  • 911
  • 1
  • 6
  • 6
70
votes
5 answers

Does the Milky Way move through space?

Does our galaxy moves through space? Or does it stay in a single location? If it does move, what causes it to move?
Mike
  • 733
  • 1
  • 5
  • 7
1
2 3
…
99 100